In the field of working on tubes, it is known to use bending tools, shears for cutting, flaring flyers, or tools for press fitting rings on the ends of a tube.
Progress in tube applications towards using multi-layer materials of the polyethylene-aluminum-polyethylene type, and towards using ever increasing tube diameters, up to 32 millimeters (mm), has caused manufacturers of apparatuses for working on tubes to develop devices that require ever increasing amounts of force to be applied to the working head. Thus, when it is desired to bend polyethylene-aluminum-polyethylene multi-layer tubes, this operation requires a high level of force (500 decanewtons (daN) to 600 daN) to be applied to the head working on the tube.
Nevertheless, using a conventional manual apparatus does not enable work to be carried out on large-diameter tubes made of the rigid multi-layer materials. The force passing via a lever arm is transformed into a force acting on the tube by engaging a transmission member, such as a tooth. The return angle through which the lever arm moves between two actuations is thus a function of the dimensioning of the engaged transmission member, and that is difficult to make compatible with the desired mechanical strength. Furthermore, the length of the lever arm is limited by the ergonomics of working with one hand only.